Oil soluble metal containing compositions and process for making same



United States Patent" G a OIL SOLUBLE METAL CONTQINING COMPOSI- TIONSAND PROCESS FOR MAKING SAME Thomas W. Mastin, Willoughby, Ohio, assignorto The Llbaizol Corporation, Wicklifie, Ohio, a corporation hio NoDrawing. Continuation of application Ser. No. 539,670, Oct. 10, 19-55.This application Sept. 26, 1958, Ser. No. 763,443

12 Claims. (Cl. 260-398) This invention relates to a novel method forthe preparation of oil-soluble compositions which contain'large .amountsof metal. In a more particular sense it relates to an improved method ofincorporating large amounts of metal with hydroxy-aromatic compounds toform oilsoluble compositions. The products which are formed by thismethod are useful as lubricant additives which may be used as dispersingagents in motor oils.

The development of the lubricant additive field in recent years hasindicated the value of the relative metal content of an additive whichis employed for its dispersant qualities. The phenomenon by whichcertain compositions are enabled to prevent the agglomeration ofinsoluble particles in a motor oil has come to be known by the somewhatmisleading term detergency, and the degree of detergency resulting fromthe use of a particular additive appears to be related not so much tothe amount of such additive, but rather to the amount of metal which ispresent in the additive.

Various metal salts are known to have sufficient dispersant propertiesto be regarded as effective detergents. Among these are the metal saltsof carboxylic acids, sulfonic acids, phenols, phosphorus acids, etc. Theterm metal salt is used to denote a compound in which all of thevalences of the metal are satisfied by attachment to the anions of theparticular acid.

It was soon learned that the basic metal salts provided a higher degreeof detergency than did normal salts.

" These basic salts were salts of polyvalent metals and were preparedquite conveniently by heating an equimolar mixture of a normal salt andthe corresponding polyvalent metal oxide or 'hydroxide. The presumedstructure of such basic salts is shownby the above illustration of abasic sulfonate,

in which a portion of the valences of the polyvalent .metalis satisfiedby attachment to hydroxyl groups. It will be noted that such basic saltscontain a higher per- ,centage of metal than do the corresponding normalsalts. A Further study showed that still higher percentages of .metalcould be incorporated into oil-soluble composi- .'tions by the use ofso-called promoters. These promoters generally are phenolic or enoliccompounds and it was found that they could be used with certainsulfonates, carboxylates, etc., to prepare oil-soluble compositionscontaining still higher percentages of metal than was possibleheretofore. Furthermore, it was learned also that these compositionspossessed even greater dispersant powers than had been realized prior tothis development.

lt is a principal object of the present invention to proflvide. a novelprocess for the preparation of oil-soluble :'compositions which containa large percentage of metal.

This also an object of the present invention to provide ice novelcompositions which may be used as lubricant additives.

A further object of the present invention is to provide an oil-solublecomposition which is an efiective dispersant when incorporated in smallamounts in motor oils.

These and other objects are accomplished by the process of preparingoil-soluble compositions containing large amounts of metal whichcomprises preparing a mixture of (a) an alkylated monohydroxy aromaticcompound, (b), and oil-soluble, metal-free non-tautomeric organic polarcompound selected from the class consisting of neutral and basiccompounds present in an amount greater than that of (a) on a weightbasis, and (c) at least two equivalents of a basic inorganic metalcompound per equivalent of (a) and heating said mixture to drive offsubstantially all free water which may be present and then treating saidwater-free mixture with an acidic gas having an ionization constantgreater than that of (a) until the titratable basicity of the mixturehas been substantially reduced.

The alkylated hydroxy aromatic compounds contemplated for use in theabove process are particularly those which yield oil-soluble metalphenates and in which an alkyl group contains at least about threecarbon atoms. Such alkyl groups as isopropyl, tertiary-butyl,Z-methylamyl-4, isoheptyl, diisobutyl, n-decyl, tetrapropyl, octadecyl,polyisobutyl (derived from polyisobutylene fractions of variousmolecular weights), etc. are illustrative of the groups which may beused. In lieu of alkyl groups, cycloalkyl groups such as, e.g.,cyclohexyl, methyl-cyclohexyl, etc. may be used. The hydroxy aromaticcompound'may contain other groups in addition to the alkyl or cycloalkylgroups. Thus, halogen, nitro, alkoxy, etc. groups may be present.Likewise the aldehyde condensation products of the above-describedalkylated hydroxy aromatic compounds are contemplated.

The basic inorganic metal compounds include principally metalic oxidesand hydroxides and in some instances the sulfides, hydrosulfides, etc.These compounds are derived from metals of groups I and ll of theperiodic table and especially suitable are those derived from metals ofthe alkali and alkaline earth subclass, particularly those derived frombarium.

As indicated this basic inorganic metal compound should be used in theprocess in an amount equal to at least two equivalents per equivalent ofthe alkylated monohydroxy aromatic compound. Inasmuch as the principalobject of the invention is to provide a process for the preparation ofoil-soluble compositions which contain large percentages of metal it isapparent that any amount of such basic inorganic metal compound inexcess of this minimum amount can be used, up to that amount which is nolonger effective to increase the proportion of metal in the oil-solubleproduct.

The process mixture generally contains some water which is added to aidin fiuidizing the inorganic metal compound. It is necessary that thiswater be removed from the mixture before the process can be elfected.Removal of the water is a simple matter, involving only its distillationfrom the process mixture. The temperature at which the mass is treatedwith an acidic gas usually is above C., and in the course of heating theprocess mixture to this temperature the last traces of free water aresubstantially eliminated.

The oil-soluble. metal-free, non-tautomeric neutral and basic organicpolar compounds are characterized by having both an oil-solubilizingsubstituent, such as a long hydrocarbon chain. and also by having anon-acidic polar group such as an ester, amide. amine. hydroxy, sulfoxy,ether, sulfide, etc. group. Some specific examples of such process ofthis invention.

.polar compounds include the following: glyceryl oleate or stearate,octadecenyl or oleyl alcohol, tridecyl alcohol, N-octadecyl propylenediamine, sperm oil, etc. The most .suitableorganic polar compounds havebeen found to be those which contain a total of at least 12 aliphaticcarbon atoms in the molecule. For an appropriate discussion of the wordtautomeric, reference may be had to Advanced Organic Chemistry, by G. W.Wheland, John Wiley & Sons, New York, 1949, chapter 14.

The use of the above-described polar compounds in "the process of thisinvention appears to have a solubilizing effect with respect to thebasic inorganic metal compound which is incorporated into the ultimateproduct. This is an unexpected function for such neutral and basicnon-tautomeric materials and it is not clear how such a function can beexplained in terms of the molecular.structure of a non-acidic compound.The previous use of such compounds in fluidizing and impartingfilterability to oleaginous compositions'is well-known, but so far as Iam aware, it has not been known that neutral or basic nontautomericmetal-free polar compounds are capable of sustaining the solubility ofotherwise insoluble metal compositions in oil which do not also containany of the wellknown dispersants, such as sulfonates or carboxylates.

It is quite probable that the neutral or basic nontautomeric polarcompound has certain hitherto unknown dispersant qualities which enableit to'preserve the basic inorganic metal compound in a colloidalsuspension, al-

though as indicated previously, it is not known just hoW it really doesoperate.

By the term acidic gas is meant one which upon reaction with water wouldproduce an acid. Thus, such gases as sulfur dioxide, sulfur trioxide,carbon dioxide, carbon disulfiide, hydrogen sulfiide, nitric oxide, etc.are exemplary of the acidic gases which are useful in the Of thesecarbon dioxide, because of its low cost and particular utility in theprocess, is preferred.

The treatment with an acidic gas is conducted in such a manner as toreduce substantially the titratable basicity of the mass. There areessentially two materials in the mass prior to carbonation which aresusceptible to reaction with the acidic gas: the free metal base (thatwhich is in excess of the stoichiornetric quantity required to form thenormal phenate) and the metal phenate. It is possible that each of thesematerials reacts with the acidic gas (e.g., is carbonated)simultaneously, but it is more likely that the excess metal base reactsfirst and when this reaction is complete the metal phenate reacts. It isunderstood of course that reaction of the metal phenate results in theliberation of the phenol from its metal salt.

The amount of acidic gas which is used in the process depends in somerespects upon the desired basicity of the particular product inquestion. Thus, in the case of a highly basic product only a smallamount of acidic gas will be required. Ordinarily, however, a less basicproduct is desired and in such instances a larger amount of acidic gasis used. A particularly preferred product is one in which the basicityhas been substantially neutralized, i.e., one in which theneutralization number is less than about 10. The preparation of such aneutral product entails the use of a rather large amount of acidic gas,i.e., more than 25 percent by weight of the amount of the metal phenatewhich is being so treated. Generally, more than the theoretical quantityof acidic gas is required to achieve any desired degree of basicity in aparticular product.

In some instances a more basic. product may be acceptable and thepreparation of such products will require the use of only -25 percent byweightof acidic gas, based on the metal phenate being treated.

Thetreatment of the above-described process mixture with acidic gasappears to have two quite beneficial effects.

-It has a clarifying effect on both the process mixture and -on theultimate product, and it allows the incorporation barium oxide.

of significantly more metal into the oil-soluble product. It is apparentthat this latter effect can be realized only when there is present inthe'reaction mixture an appreciable quantity of oil-insoluble metalbase. Thus, it is important for the incorporation of the maximum amountof metal that the process mixture not be separated (as, e.g., byfiltration) from gil-insoluble metal base before carbonation.

The compositions which may be prepared by the process of this inventionare readily adaptable for use as dispersants in motor oils. Suchcompositions provide a desirable alkaline reserve in a crankcase and aresatisfactorily stable over long periods of time under the conditions ofnormal engine operation.

Although mineral lubricating oils containing the modified metal saltsdescribed herein are valuable in lubricating oils, it is sometimesdesirable to include one or more other dispersants and/or one or moreanti-oxidants or anticorrosion agents in the final lubricating oilcomposition along with these modified salts,

Dispersants which may be so employed include principally the metalmahogany sulfonates. 'Such sulfonates may be either the normal or thebasic sulfonates. A particlularly preferred supplemental dispersantwhich may be employed is an acidic gas-treated basic sulfonate. Such aproduct is prepared merely by heating a normal metal sulfonate with abasic metal compound and then treating the product with acidic gas.

The following examples illustrate some of the details of the process ofthis invention. The term metal ratio employed in this specification isthe ratio of total metal in the oil-soluble composition to totalequivalents of alkylated hydroxy-aromatic compound present. It is thus aconvenient measure of the amount of excess metal present in thecomposition, i.e., that amount of metal in excess of the stoichiometricamount required to satisfy the organic salt-forming anions presentExample 1 A sulfoxide was prepared treating polyisobutylene of 750average molecular weight with 47.5 percent of its weight of SOCl for 4.5hours at 200-220 C. A mixture of 787 grams (1.0 equivalent) of thissulfoxide, 124 grams (0.6 equivalent) of diisobutyl phenol, 550 grams ofmineral oil and 200 grams of water was warmed to 70 C. and then treatedwith 306 grams (4.0 equivalents) of barium oxide. This mixture washeated at reflux temperature for one hour and then treated at C. withcarbon dioxide until the mixture was substantially neutral. Theresulting mixture was filtered through Hyfio to yield a clearoil-soluble liquid having the following analyses:

To a mixture of 268 grams (1.0 equivalent) of oleyl alcohol, 675 gramsof mineral oil, 124 grams (0.6 equivalent) of diisobutyl phenol, and 146grams of water, at 70 C. there was added 308 grams (4.0 equivalents) ofThis mixture was heated at reflux temperature for one hour, then at 150C. while a' stream of carbon dioxide was bubbled through the mixtureuntil it was substantially neutral. The thus acidified mixture wasfiltered and the clear brown oil-soluble filtrate found to have thefollowing analyses:

Percent sulfate a 29.8 Neut. No. (basic) 2.6 Metal ratio 2 6.0

Example 3 'alents) of barium oxide and then heated to 150 C. A stream ofcarbon dioxide was bubbled into the mixture at this latter temperatureuntil the mixture was substantially neutral. Filtration through Hyfloyielded a clear brown oil-soluble filtrate with the following analyses:

Percent sulfate ash 23.4 Neut. No. (basic) 6.7

Metal ratio Example 4 To 'a mixture of 268 grams (1.0 equivalent) ofoleyl alcohol, 124 grams (0.6 equivalent) of heptyl phenol, 1034 gramsof mineral oil, and 190 grams of water there was added at 70 C. 306grams (4.0 equivalents) of barium oxide. This mixture was heated atreflux temperature for an hour. and then treated with sulfur dioxide at150 C.. until the mixture was acidic. The mixture was filtered throughHyflo to yield a product having the following analyses:

Percent sulfate ash 20.9

Neut. No. "(acidic)" 3.0

Metal ratio 5 3 Example 5 To a mixture of 268 grams (1.0 equivalent) ofoleyl alcohol, 124 grams (0.6 equivalent) of heptyl phenol, 988 grams ofmineral oil and 160 grams of water there was added 168 grams (4.0equivalents) of lithium hydroxide monohydrate. This was heated at refluxtem- *perature for an hour and then treated with carbon dioxide at 150C. until it was substantially neutral. Filtration of this carbonatedmixture yielded a liquid having the following analyses:

Percent sulfate ash 112.7

Ne'utINo. (basic) 20 Metal ratio 5.8 Example 6 To a mixture of 500 grams1.0 equivalent) of polyisobutylphenoxycthanol, 124 grams (0.6equivalent) of heptyl phenol, 848 grams of mineral oil and 190 grams ofwater there was added at 70 C., 306 grams (4.0 equivalents) of bariumoxide. This mixture was heated at reflux temperature for an hour at 150C. while bubbling carbon dioxide beneath the surface for three hours.The carbonated mixture was filtered through Hyflo to yield a liquidproduct having the following analyses:

Percent sulfate ash 23.8

Neut. No. (basic) 9.7

Metal ratio 6.3

Example 7 Percent sulfate ash 31.2

Neut. No. "(acidic)" 0.4

Metal ratio 6.3

Example 8 A mixture of 1269 grams (3.0 equivalents) of sperm oil, 522grams (1.8 equivalents) of a heptyl phenolformaldehyde condensationproduct, 2l69 grams of mineral oil, 540 grams of water was treated at 70C. with 1134 grams (14.8 equivalents) of barium oxide. This mixture wasstirred at reflux temperature for one hour then at 150 C. while carbondioxide was bubbled be- 56. a, neath the surface. Filtration yielded aclear liquid having the following analyses:

Percent sulfate ash 32.7

Neut. No. (basic) 1.9 Metal ratio 8.2

Example 9 To a mixture of 915 grams (2.2 equivalents) of a sulfurizedsperm oil, 273 grams (1.3 equivalents) of diisobutyl phenol, 1715 gramsof mineral oil, and 396 grams of Water there was added at C. 833 grams(10.8 equivalents) of barium oxide. This mixture was heated at refluxtemperature for an hour and then at 150 C. at which temperature carbondioxide was bubbled through the mixture until it was substantiallyneutral. The mixture was filtered through Hyflo to yield a liquid havingthe following analyses:

Percent sulfate ash 28.7

Neut. No. (basic) 2.9

Metal ratio 7.0 Example 10 To a mixture of 174 grams (1.0 equivalent) ofN-octadecyl propylene diamine, 124 grams (0.6 equivalent) of diisobutylphenol, 766 grams of mineral oil, 146 grams of water there was added 306grams (4.0 equivalents) of barium oxide and the whole was refluxed foran hour. Water was removed by raising the temperature to 150 C.whereupon carbon dioxide was bubbled through the mixture at thistemperature until it was substantially neutral. The mixture was filteredthrough Hyflo to yield ,a clear oil-soluble liquid having the followinganalyses:

Percent sulfate ash Neut. No. (basic) 2.5 Metal ratio 5.8

Example 11 Percent sulfate ash 29.6 Neut. No. (basic) 0.8 Metal ratio7.4

The use of larger amounts of the basic metal compound of component (c)in the process is shown by the tabulated data of Examples 12-16. Each ofthese examples involved the reaction of 1.0 equivalent of sperm oil,0.15 equivalent of diisobutyl phenol and a variable amount of bariumoxide as indicated in the table. Water was used in an amount equal to15% of the total reaction mixture and an amount of oil was used as adiluent such that the theoretical sulfate ash content of the mixture was32.0%. The procedure of Example 7 was followed.

Percent Neut Metal Ex. No. BaO (c)/(a) sullglte No. Ratio 3. 25 30. 4 0.5A 23. 8 5.25 35 31.0 0.713 34.0 7. 5 50 30. 4 1. 0B 47. 5 11.3 75 26.2 1. 3B 61. 5 15.0 20. 1 1. 4B 62. 8

It will be noted that the incorporation of increased amounts of metalinto the oil-soluble product continues to characterize the process whenthe ratio to (a) is as high as 75 :1, but that further increase of thisratio has very little elfect with respect to the incorporation of metalinto the oil-soluble product.

This application is a continuation of application Serial No. 539,670,filed October 10, 1955, now abandoned.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. The process of preparing oil-soluble compositions containingstochiometrically large amounts of metal which comprises preparing amixture of (a) an alkylated phenol,

(b) an oil-soluble, metal-free, non-tautomeric polar compound having atleast 12 aliphatic carbon atoms, selected from the class consisting ofsulfoxides, esters, alcohols and amines in an amount greater than thatof (a) on a weight basis, and

(c) at least two equivalents of a basic inorganic metal compoundselected from the class consisting of barium and lithium oxides andhydroxides, per equivalent of (a), and

heating said mixture to drive ofi substantially all free water which maybe present and then treating said waterfree mixture with an acidic gasselected from the class consisting of carbon dioxide and sulfur dioxideuntil the titratable basicityof the mixture has been reduced to a basenumber less than 10.

2. The process of claiml characterized further in that the oil-soluble,metal-free compound of (b) is a neutral compound. i

3. The process of claim 1 characterized further in that the alkylatedphenoliccompound of (a) is diisobutyl p e ol- V a 4. The process ofclaim 1 characterized further in that the oil-soluble, metal-free,non-tautomeric polar compound of (b) is an alcohol.

5. The process of claim 1 characterized further in that the oil-soluble,metal-free, non-tautomeric polar compound of (b) is an ester.

' 6. The process of claim 1 characterized further in that theoil-soluble, metal-free, non-tautomeric polar compound of (b) is spermoil.

7. The process of claim 1 characterized further in that at least5.0'equivalents of the basic inorganic metal compound of (c) is used perequivalent of (a).

8. The process of claim 1 characterized further in that the acidic gasis carbon dioxide.

9. The process of claim 1 characterized further in that the basicinorganic metal compound of (c) is present in the mixture in an amountup to the limit of solubility of the metal in the product of theprocess. 7

10. The process of claim 1 characterized further in that the basicinorganic metal compound of (c) is present in the mixture in an amountup to about equivalents per equivalent of (a).

11. The process of claim 1 characterized further in that the productthereof has a metal ratio up to about 12. The process of claim 1characterized further in that the alkylated phenol of (a) is heptylphenol.

References Cited in the file of this patent UNITED STATES PATENTS2,616,924 Assef et al. Nov. 4, 1952

1. THE PROCESS OF PREPARING OIL-SOLUBLE COMPOSITIONS CONTAININGSTOCHIOMETRICALLY LARGE AMOUNTS OF METAL WHICH COMPRISES PREPARING AMIXTURE OF (A) AN ALKYLATED PHENOL, (B) AN OIL-SOLUBLE, METAL-FREE,NON-TAUTOMERIC POLAR COMPOUND HAVING AT LEAST 12 ALIPHATIC CARBON ATOMS,SELECTED FROM THE CLASS CONSISTING OF SULFOXIDES, ESTERS, ALCOHOLS ANDAMINES IN AN AMOUNT GREATER THAN THAT OF (A) ON A WEIGHT BASIS, AND (C)AT LEAST TWO EQUIVALENTS OF A BASIC INORGANIC METAL COMPOUND SELECTEDFROM THE CLASS CONSISTING OF BARIUM AND LITHIUM OXIDES AND HYDROXIDES,PER EQUIVALENT OF (A), AND HEATING SAID MIXTURE TO DIRVE OFFSUBSTANTIALLY ALL FREE WATER WHICH MAY BE PRESENT AND THEN TREATING SAIDWATERFREE MIXTURE WITH AN ACIDIC GAS SELECTED FROM THE CLASS CONSISTINGOF CARBON DIOXIDE AND SULFUR DIOXIDE UNTIL THE TITRATABLE BASICITY OFTHE MIXTURE HAS BEEN REDUCED TO A BASE NUMBER LESS THAN 10.